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by phickey 269 days ago
https://github.com/WebAssembly/custom-page-sizes is a proposal championed by my colleague to add single byte granularity to Wasm page sizes, motivated by embedded systems and many other use cases where 64kb is excessive. It is implemented in wasmtime, and a Firefox implementation is in progress.
1 comments
IshKebab 269 days ago
> Allow Wasm to better target resource-constrained embedded environments, including those with less than 64 KiB memory available.

If it has less than 64 kB of memory how is it going to run a WASM runtime anyway?

And even cheap microcontrollers tend to have more than 64 kB of memory these days. Doesn't not seem remotely worth the complexity.

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Ductapemaster 269 days ago
It's not about the whole microcontroller having less than 64kB of memory - it's that each WASM module has a minimum memory size of 64kB, regardless of how much it actually requires. Also, if you need 65kB of memory, you now have to reserve 2 pages, meaning your app now needs 128kB of memory!

We're working on WASM for embedded over at atym.io if you're interested.

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titzer 269 days ago
> If it has less than 64 kB of memory how is it going to run a WASM runtime anyway?

There is WARDuino (https://github.com/TOPLLab/WARDuino and https://dl.acm.org/doi/10.1145/3357390.3361029).

A runtime that accepts Wasm modules that use a large fraction of the functionality, there is going to be a RAM requirement in the few KiB to few tens of KiB. There seems to be a branch or fork of Wasm3 for Arduino (https://github.com/wasm3/wasm3-arduino).

If you are willing to do, e.g. Wasm -> AVR AOT compilation, then the runtime can be quite small. That basically implies that compilation does not happen on device, but at deployment time.

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